1. Field of the Invention
The present invention relates to a communication apparatus, and in particular to a communication apparatus performing a communication function maintenance/diagnosis in a communication system using IP packets.
2. Description of the Related Art
In a communication system using IP packets, a communication function maintenance/diagnosis have been performed in order to detect abnormalities of various kinds of communication devices and to provide maintenance thereof. As will be described hereinafter, there are known as representative examples, (1) a method in which a CPU in charge of management operation of communication functions is given an interrupt notification upon occurrence of an abnormality of a communication device, and (2) a method in which a CPU periodically performs polling for detecting abnormalities of the communication devices.
Firstly, the former method that is the communication function maintenance/diagnosis method (1) will be described referring to FIGS. 7 and 8. It is to be noted that a partition among hardware 100, software 200, and an operation manager or upper-level CPU 300 shown in FIG. 7 indicates roughly partitioned functions but not an exact partition thereof.
This method incorporates an abnormality detector 10 provided with an indicator 11 and an interrupt controller 12 for the function of the hardware 100, and a CPU 20 located on the border of the functions of the hardware 100 and the software 200.
The indicator 11 in the abnormality detector 10 is generally composed of a register whose bits are associated with diagnosed devices (not shown). The interrupt controller 12 generates an interrupt signal to the CPU 20 as necessary.
In operation, when the abnormality detector 10 receives an abnormality notification S1 from one of the devices connected to the hardware 100, the bit of the corresponding device is changed to a value of an abnormal state in the indicator 11, and an interrupt notification S2 is provided by the interrupt controller 12 to the CPU 20.
The CPU 20 having received the interrupt notification S2 accesses the indicator 11 and performs questioned point identification processing S3 so as to identify which of the devices is abnormal. Thereafter, the CPU 20 provides a notification S30 related to the abnormality occurrence to the operation manager or upper-level CPU 300, and directly accesses the abnormal device to provide status information acquisition processing S4, thereby acquiring detailed status information.
It is to be noted that the above-mentioned notification S30 related to the abnormality occurrence can be performed, for example, by illuminating an LED corresponding to the abnormal point, or the like in case of notification to the operation manager.
FIG. 8 shows an internal arrangement of a router X adopting such a communication function maintenance/diagnosis method (1). As shown, the router X is composed of devices 1-3 connected with a line bus 5 sequentially from a line interface 4, the CPU 20 connected to the devices 1-3 respectively with a PCI bus 6, and the abnormality detector 10 connected to the CPU 20 with the CPI bus 6. Namely, FIG. 8 shows the connection relationships between the abnormality detector 10 as well as the CPU 20 and the devices 1-3 shown in FIG. 7.
Also, a content addressable memory 7 is connected to the device 3. The content addressable memory 7 has e.g. IP address information as an entry, and is used in ordinary IP packet processing.
In operation, for example, when a failure occurs in the device 2, the abnormality notification S1 is provided from the device 2 to the abnormality detector 10. The abnormality detector 10 having received this notification indicates the abnormality of the device 2 with the corresponding bit of the indicator 11 and provides the interrupt notification S2 from the interrupt controller 12 to the CPU 20.
The CPU 20 having received the interrupt notification S2 performs the questioned point identification processing S3 to identify that the device 2 is abnormal, so that by accessing the device 2 through the PCI bus 6 the CPU 20 performs the status information acquisition processing S4.
It is to be noted, although not shown in FIG. 8, the devices 1-3 and the abnormality detector 10 are mutually connected respectively with a control line, and that the interrupt controller 12 of the abnormality detector 10 and the CPU 20 are also mutually connected with a control line. Therefore, the above-mentioned abnormality notification S1 and the interrupt notification S2 are respectively notified instantaneously through the control lines.
The communication function maintenance/diagnosis method (2) will be described referring to FIG. 9. In FIG. 9, it is to be noted that an abnormality detector 30 and a CPU 40 respectively substitute for the abnormality detector 10 and the CPU 20 of FIG. 7. The abnormality detector 30 has an indicator 31 similar to the indicator 11 in the abnormality detector 10 but does not have a functional part corresponding to the interrupt controller 12. Also, FIG. 9 is different from FIG. 7 in that the CPU 40 periodically performs questioned point identification processing S5 by a periodical polling.
In operation, when the abnormality detector 30 receives the abnormality notification S1 from one of the devices, a bit of the corresponding device is changed to a value of an abnormal state in the indicator 31.
As described above, since the CPU 40 performs the questioned point identification processing S5 by the periodical polling. Therefore, when an abnormality of any of the devices is indicated by the indicator 31 at the time of this processing S5, the CPU 40 can detect the abnormality and can identify the questioned point.
When the questioned point can be thus identified, the CPU 40 provides a notification S30 related to the abnormality occurrence to the operation manager or the upper-level CPU 300, and directly accesses the abnormal device and performing status information acquisition processing S6, thereby acquiring detailed status information.
As a communication function maintenance/diagnosis method other than the above-mentioned methods (1) and (2), there is one which can always monitor signal lines by a loopback test and can perform remote control, that relates to a maintenance/operation management function of a network to which a plurality of communication apparatuses are connected, (see e.g. patent document 1).
In this method, there are a first circuit for inserting management data such as test data into a preamble of a packet to be transmitted to a general-purpose interface and for detecting the management data such as test data returned by being inserted in an idle time between packets received from the general-purpose interface, and a second circuit for detecting the management data inserted into the preamble of the packet to be received from the general-purpose interface and for inserting the management data into the idle time of the general-purpose interface. Also, the second circuit detects the test data inserted into the preamble to be returned in the idle time of the general-purpose interface, thereby performing the loopback test.
Also, there is a communication function maintenance/diagnosis method that realizes a highly reliable maintenance/diagnosis while avoiding misdiagnosis caused by a failure on a maintenance interface abnormality processing side (see e.g. patent document 2).
In this method, the maintenance interface selects an abnormality occurrence pattern corresponding to a maintenance/diagnosis request from an operator from among a group of abnormality occurrence pattern libraries and an abnormal pattern generator generates an abnormal cell corresponding to the abnormality occurrence pattern to be transmitted to the node at the diagnosed point. Also, in the node at the diagnosed point, the abnormality detector detects the received abnormal cell and an abnormality analyzer/notifier analyzes the abnormality by comparing the abnormality with a failure database, thereby checking whether or not the abnormality detection side operates appropriately against pseudo-failure.    [Patent document 1] Japanese patent application laid-open No. 2003-169093    [Patent document 2] Japanese patent application laid-open No. 7-11104
In the above-mentioned communication function maintenance/diagnosis method (1), since the interrupt controller 12 of the abnormality detector 10 having received the abnormality notification S1 immediately performs the interrupt notification S2, a lapse between an occurrence of a failure in a certain device and a reception of the interrupt notification S2 by the CPU 40 is short. However, since both of the questioned point identification processing S3 and the status information acquisition processing S4 performed thereafter by the CPU 20 before acquiring required status information are performed through the PCI bus 6 that is a bus of relatively low speed of the order of 33 MHz, the CPU processing occupation time is extended in accordance with the increase in number of devices that are objects for the status information acquisition.
On the other hand, in the above-mentioned communication function maintenance/diagnosis method (2), since the CPU 40 performs the questioned point identification processing S5 by polling, the detection of the abnormality of the device and the identification of the questioned point can be simultaneously performed. Therefore, only the status information acquisition processing S6 is required to be performed in order to acquire the required status information.
However, since the status information acquisition processing S6 is also performed through the PCI bus, the CPU processing occupation time is extended in accordance with the increase in number of devices that are objects for the status information acquisition.
Also, there are problems that periodically performed polling requires the CPU processing, and that the CPU 40 cannot detect the abnormality until the next polling is performed, depending on the timing of the abnormality notification S1.